They were joined on the French Riviera by gorgeous co-stars Brittany Murphy and Jessica Alba.

Owen, 40, best-known throughout the Nineties for his role in TV show Chancer, is now one of Hollywood's most bankable stars thanks to his Golden Globe-winning performance in Closer.

"I've had the most fantastic time in the past couple of years," he told a festival press conference.

"Getting involved with this project was a huge deal for me. When I first saw the finished film I was completely blown away."

The film, set in a seedy and crime-ridden fictional city, has attracted criticism in the US for its gory scenes - in one Owen is seen speaking to a severed head.

Feminists have been angered that most of the women in the movie are scantily-clad strippers and prostitutes.

But writer Miller defended the movie, saying: "I'm a guy. When I created Sin City I decided the guys would all be tough, the women would all be beautiful and the cars would all be vintage.

"Cartoonists do things that are fun to draw. I like scantily clad women."

He countered criticism that violent films might contribute to a more violent society.

"Violence is a real catchy buzzword these days. Considering most drama since The Iliad and before is extremely violent, because that's how people work problems out, it's a bit ridiculous. I don't believe in the 'monkey see, monkey do' theory of entertainment," the American said.

"The Japanese have the most violent fiction and movies in the world and they have among the lowest crime rate."

Sin City, filmed almost entirely in black and white, consists of several different stories.

Owen plays one of the film's only good guys, an ex-photographer who protects the city's prostitutes.

Rourke plays a streetfighter out to avenge a beautiful woman's death while Bruce Willis, who could not make the festival, is a cop jailed for a crime he didn't commit.

Although it relies heavily on digital effects to create the background to each scene, director Robert Rodriguez made Sin City for just £24 million.